The present invention relates to a material for treatment of cerebral infarction and to a brain tissue regeneration method using the material for treatment of cerebral infarction.
Cerebral angiopathy is the second leading cause of death in Japan and is responsible for the greatest cause of being bed-ridden, while not causing death. Therefore, the aging society is in urgent need of development of therapy appropriate for cerebral angiopathy.
Among cerebral angiopathies, ischemic cerebrovascular disease such as cerebral infarction or cerebral thrombosis occurs with the highest frequency. Mortality due to cerebral infarction is greater than the total mortality due to myocardial infarction and ischemic heart disease.
If the cause of paralysis is cerebral infarction, current treatment is thought to be effective within 3 hours after development, at present.
In addition, rtPa (recombinant tissue plasminogen activator) intravenous drip treatment can be expected to have recanalization effect and offers functional recovery of up to approximately 30% of damaged brain function.
However, the rtPa intravenous drip treatment has the disadvantage that it is used in only approximately 2% of cases due to adverse reactions of intracerebral hemorrhage.
Moreover, thrombolytic therapy using catheters has been approved by the Ministry of Health, Labour and Welfare of Japan. However, under the present circumstances, no drug used in this therapy is covered by national health insurance.
In the adult brain, the region where new neurons are produced is thought to be located in the lateral subventricular zone and in the granular cell layers of the hippocampal dentate gyrus.
In addition, new neurons formed after cerebral infarction are derived from the lateral subventricular zone. These neurons migrate to the parenchyma of the corpus striatum to form chain-like cell aggregates, which in turn differentiate into nerves of the corpus striatum and form synapses.
Moreover, blood vessels are thought to participate in the control of neural progenitor cell differentiation and influence induced nerve regeneration in the corpus striatum.
The development of therapy based on regenerative medicine has been pursued for cerebral infarction, and preclinical experiments using rat or mouse models of cerebral infarction have been practiced.
Stem cells derived from bone marrow, peripheral blood, adipose, or umbilical cord blood, or the like are used as transplanted cells. Embryonic neural stem cells or ES cells, or the like are also used. These cells are injected into the brain or veins.
As a result, these cells may directly differentiate into nerves, thereby decreasing cerebral infarction regions, restoring brain function, or may promote angiogenesis in peri-infarct areas.
For example, Japanese Patent Laid-Open No. 2007-130026 discloses a method for efficiently inducing in vitro or in vivo the growth of neural stem cells that are important for, for example, the treatment of nerve injury sites caused by cerebral infarction.
In addition, for example, Japanese Patent Laid-Open No. 2007-014780 discloses pharmaceuticals for cerebral infarction regions comprising mesenchymal stem cells and IGF-1 in combination.
However, these techniques have a difficulty in offering efficient functional recovery in cerebral infarction regions. Thus, an effective approach for ameliorating angiopathy at a cerebral infarction region and improving brain function has been demanded.